Fluid motor



Oct. 16, 1956 KRAUT' 2,766,735

FLUID MOTOR Filed June 15, 1955 INVENTOR- MA X KIM U T 5 ATTORNEY United States This invention relates to fluid motors and more particularly to such fluid motors capable of imparting a differential of reciprocating motion, the operating fluid being liquid or gaseous such as compressed air. Such motor apparatus is especially eflective and desirable in imparting differential reciprocation to shaking screens, shaking tables, jigs and the like, in recovery of mineral value and particularly in such recovery as applied to concentration of mineral values in a slime concentrator. It is desirable that this reciprocating motion of such concentrating apparatus shall be controllable through the motor as to length or amplitude of movement, speed or timing of number of reciprocations per minute, differential of speed of such reciprocations as between respective opposite directions of reciprocations, that is, preferably relatively slow in one direction and relatively rapid in the opposite direction, and that all of such adjustments may be made through the motor as the primary force of such movement while the apparatus is in operation. Because of the forces of gravity such motor as herein exemplified is preferably mounted on a vertical axis and the resultant forces applied to vertical reciprocating movement of a jig or the like. If, however, it is desired to translate the vertical reciprocation to horizontal reciprocation, such force may be translated by suitable leverage in a well known manner.

Briefly, the invention comprises a fluid motor having a cylinder chamber and piston therein actuated on an upward stroke by fluid inflow, and an outflow valve in the head of the cylinder pressure chamber opened by the interaction of piston and spring means operative through a valve rod slidable in a tubular piston shaft, the downstroke of the piston actuating the valve rod to close the valve responsive to gravitational weight of the assembly of piston, shaft and operating facilities connected thereto.

One form in which the invention may be exemplified is described herein and illustrated in the accompanying drawing which is made a part of the specification.

In the drawing:

Fig. l is a central vertical transverse section of the invention on line 1-1 of Fig. 2.

Fig. 2 is a horizontal transverse section on line 22 of Fig. 1.

Referring to the drawing in which like reference characters indicate corresponding parts in the several views, the motor consists of a piston cylinder chamber 1 which is closed at the top by a closure plate 2 having centrally thereof an opening 2a from the edges of which there is axially extended a cylindrical guide member 3 which encloses therein a wear bushing 3a. Circumferentially spaced radially outwardly from the extension 3 is an annular upstanding lug providing an annular groove 212 for footing therein a spring to be described.

At the bottom the cylinder chamber is closed by a plate 4 having centrally thereof an axial opening 4a in which is securely mounted an outlet nipple 5 to which any Suitable outlet conduit may be connected, and in which there is positioned a control valve 5a.

2,755,735 Patented Got. 16, 1956 Adjacent to the bottom, and preferably in the side wall of the cylinder, there is provided an inlet opening 6 for a fluid supply pipe to a suitable fluid source, such as a pump (not shown), the fluid supply pipe having therem a control valve 6a. The outlet opening 4a and nipple 5 are of greater diameter and flow capacity than the inlet opening 6. At the upper portion of the side wall of the cylinder chamber is an outlet vent opening 7 COlTlITllllllcating to atmosphere.

Slidably reciprocable within the cylinder is a piston 8 having the usual sealing rings, the piston providing a pressure chamber 1a in the cylinder. Rigidly connected axially to the piston and extending at one side therefrom is a hollow tubular shaft 9 which extends slidably through the extension 3 of the piston chamber and the bushing 3a, the opposite end of the shaft having supporting connection to the central portion of a cross-arm 10 which has its two arms extending oppositely laterally. At each of the opposite terminal end portions of the cross-arm it? there is a suitable means, such as clamp casing lltla, for a secure attachment thereto of suspension cables, rods, bars and the like indicated 10b, the opposite ends of which may be connected to any suitable prime operating means of the facility or apparatus which is to be operated by the fluid motors, such as, for example, the lever yoke A of a concentrating jig, shown diagrammatically. Manifestly the piston 8, tubular shaft 9 and cross-arm it reciprocate as a unit. Transversely through tubular shaft 9 there is an axially elongated slot 9a for the length of maximum stroke of the piston 8, the opposite ends thereof being 9b and 9c.

A valve rod 11 is slidably mounted within the tubular shaft 9, said valve rod having a portion of its lower end extending through and beyond the piston, and being coaxial with the piston and the outlet opening 4a of nipple 5. At said lower end of the valve rod there is mounted a relatively flat circular valve disc 12 which may be of rigid material for relatively rapid operation of the motor, but which, for the desired relatively slow operation in concentration of slimes, is preferably flexible with a degree of resilience, such as tough rubber composition. The body of the valve disc 12 is reinforced centrally at its underface by a plurality of underlying supplemelr tal discs of graduated smaller diameter, indicated as a group 12a, which leave the outer circumferential portion of the valve disc 12 free for sealing contact. A rigid disc 12b may underlie said supplemental valve disc assembly 12a, said valve disc 12 and its supplemental assembly being maintained on the end of the valve rod by lock nuts 120. At the opposite or upper face of the valve disc there may be a rigid plate 12d mounted on the valve rod against a shoulder, the plate being of lesser diameter than the valve disc to maintain the central portion of the disc reinforced while permitting flexibility to that radially outer portion which contacts the valve seat. Between the upper reinforcing plate 12a and the head face of the cylinder 8, there may be a disc bumper cup 8:: carried by the valve rod and transmitting direct pressure from the piston to the valve assembly.

At its opposite upper end the valve rod 11 is threaded at 11a, and upon said threaded portion is mounted an adjustable cupped disc spring bearing plate and contact member 13 having a hand-grip portion 13a, and the underface of which provides an annular contact face 13b facing the cross-arm 10, said cupped disc being lockable at selectively adjustable positions by wing nut 13c.

The valve rod has a short transverse slot 1112 therethrough Within the zone of the 'slot 9a of the tubular piston shaft. Passing through the slot 11b, and through the slot 9a in the piston shaft 9 there extends a transverse bar 14 which snugly fits slot 11b, said bar being attached at its opposite ends to and extending across the diameter of the upper face of a cupped disc plate 15, as by ears 16, the opposite face of the disc plate having an annular recess 15a for receiving therein the upper end of a coil spring 17, the opposite end of which is footed in the annular groove 2b upon the upper closure plate 2 of the cylinder chamber. A resilient bumper thrust ring 14a circumferentially of the piston shaft 9 is interposed between the bar 14 and the crossa1'm 19 for receiving the thrust therebetween, said bumper ring having an axial width suflicient to extend somewhat below the upper end of the slot 9a in the shaft 9 to receive the thrust and impact between the cross-arm and the bar 14.

Again referring to the cross-arm 10, there is mounted at the upper face thereof a spring cylinder cup contact member 19 of substantial depth, in which is mounted one end of a valve-rod coil spring 26, the opposite end of which bears against the adjustable cup spring bearing plate or contact member 13, the spring being radially spaced circumferentially of the valve rod 11 and coaxial therewith. The spring cup contact member 19 is provided at its upper open end with a radially outward flange 19a providing at its terminal end a contact face 1% having equal diameter as the bottom face 13b of the adjustable disc 13. A resilient bumper ring 190 is preferably mounted on said contact face 1%, to provide a resilient buffer between the faces 1% and 13b. It is the relative position between these faces which determines the desired length of stroke of the piston.

Since there is substantial thrust in closing of the valve 12, the inner bottom wall of the cylinder chamber 1 may be provided with a resilient bumper plate 21, manifestly having an opening 21a registering with the outlet opening 4a and nipple 5. Such a plate is especially desirable when a flexible resilient valve 12 is employed.

It is manifestly desirable that the excursion of the stroke of piston 8 shall stop in spaced relation to the bottom of the cylinder chamber. Wherefore, resilient rubber bumpers members 22 may be provided mounted upon posts 23 upstanding from said bottom of the cylinder, to support the weight and take the thrust of the piston and shaft 9 with the attendant cross-arm and weight of the operated apparatus A attached to the crossarm by the suspension members 10!). Preferably there are three or four of such bumper members circularly spaced inwardly from the inner wall of the cylinder chamber.

In operation of the apparatus, any pressure fluid, liquid or gaseous, enters the pressure chamber 111 of the cylinder through valve-controlled opening 6 forcing the assembly of piston 8, tube shaft 9, cross arm 10, and including the connected weight of concentrating jig apparatus A, to be actuated upwardly at a speed controlled by the inlet valve 6a in the conduit of the inlet opening 6. While the piston and said assembly is initially moving upwardly, the valve rod 11 is stationary because the cross-bar 14 is slidable lengthwise of the shaft slot 9a, and valve disc 12 is thus held in closed position by the fluid pressure on the disc valve 12 in cylinder chamber 1a, and thus keeping the discharge outlet of nipple 5 closed until the rim 19b, 19c of contact cup 19 engages the under face 13b of plate 13 which lifts the valve rod and the valve 12, the resilient bumper 19c absorbing the impact of such contact. Such upward movement manifestly compresses spring 20. A slight initial lift of the valve rod 11 lifts the valve disc 12 from its seat to a corresponding extent, resulting in immediate loss of pressure as the fluid pressure medium escapes from the pressure chamber 1a through the relatively large outlet opening of nipple 5. In the closed position of the valve 12, the spring 17 is compressed between the cupped plate 15 and groove 21), and is maintained so compressed by the pressure on valve disc 12 through valve rod 11, bar 14 and cup 15. Upon said momentary slight release of pressure on the valve disc 12, the spring 17 actuates cupped plate 15 upwardly including bar 14 in the slot 11b of the valve rod 11 and thus-throws the valve seat violently wide open. The shaft 9 will have been previously raised by the piston'so that the bar 14 will be adjacent to the bottom end 9c of slot 911 and is thus in position for raising responsive to spring 17.

The rapid escape of the fluid pressure medium in pres sure chamber 1a through the relatively large discharge outlet opening 5 causes complete loss of pressure therein, with consequent rapid downward motion of the piston with the weight of its said assembly of shaft 9, cross-arm lo and attached weight of apparatus A. Manifestly this is the exhaust stroke of the piston. During this exhaust stroke the expanded excursion of spring 17 holds the valve 12 open until, at the end and completion of the stroke, the rubber cushion 14a contacts bar 14 and thereby forces down the valve rod 11. to reseat the valve 12 to closed position, and simultaneously compressing spring 17, completing the cycle.

To insure the rapid opening of the valve, on the partial release of pressure when the valve discis slightly raised, the spring 2'9 becomes compressed on the upstroke before the contact face 1% of cup 19 (or of bumper ring 19s,.if employed), touches the contact face 13b of the springbearing contact cup 13, and thus promotes the quick upward thrust of valve rod 11 and disc 12. h

The downstroke of the piston, which obviously is quite violent due to the weight factor, is partially cushioned by bumpers 22 which prevent the piston with its connected weight from forcing the valve disc below its seat which would cause rapid wear and failure of the valve. The downstroke may also be selectively regulated and controlled by means of the valve 5a which communicates with the outlet nipple 5. As stated, the relative position of members 19 and 13 determines the length of stroke desired in the piston, such stroke being adjustable by adjusting the plate 13 upwardly or downwardly on the threads 11a of rod 11. Timing or speed of the upper strokes per minute is regulated and controlled by the fluid inlet valve 6a; and independently, the timing or speed of the downward stroke per minute may be regulated and controlled by the fluid outlet valve 50:, thus making it possible to attain any desired differential in upward or downward motion. 7 v

It is to be noted that without action of spring 17 and 24), which maintains the valve 12 open until completion of the downward piston stroke, an objectionable fluttering or vibratory motion of the piston occurs at either beginning or end of the stroke, which has the eifect of entirely destroying the objective of the motor.

In connection with the employment of either a flexible or rigid valve disc 12, reference has been made to relatively slow upward stroke and relatively rapid downward strokes of the piston. An example of such relatively slow stroke would be about '18 to ZOstrokes per minute, in which operation it is desirable or necessary that the valve disc be flexible; but-at about30 to 40 or more strokes per minute, either a flexible or a rigid metal disc valve operates satisfactorily. In the example of operation of concentrating slimes, acceptable results are only attained with relatively slow upward strokes and more rapid, or violent downward strokes, which is the reason for the preference ofthe flexible disc'valve 12.,

Having thus described the invention, what is claimed as new and patentable is:

l. A fluid motor comprising a cylinder chamber, a piston reciprocable in the cylinder chamber providing a pressure chamber at one end of the cylinder having an inlet and an outlet for the operating fluid, a tubular piston shaft having one of its ends connected axially to the .piston and extending upwardly therefrom beyond the cylinder chamber, said shaft having an axially elongated slot transversely therethrough, 'a cross-arm mounted'transversely at the upward end of said piston shaft, a contact member at the upper side 'ofthe cross-arm, -'said piston shaft, cross-arm and contact member being reciprocable in unison'by. the piston, a. valve rod slidably mounted coaxially within the tubular piston shaft and having its upper end portion extending beyond the cross arm and said contact member, a spring-bearing contact member adjustably mounted at said extended upper end portion of the valve rod, a first spring member mounted between said adjustable spring-bearing contact member and said first-mentioned contact member, the said contact members being adapted for relative contact by the upward stroke of the piston and thereby lifting the valve rod, a valve member mounted at the opposite lower end of the valve rod adapted to open and close the outlet of the pressure chamber responsive to reciprocation of the valve rod, said valve being initially opened by lifting of the valve rod by said contact of said members, and a second spring means between the cross-arm and cylinder, connecting means between said second spring and the valve rod whereby the expansion excursion of said second spring may actuate the said rod to open the valve, said connecting means being slidable in the elongated transverse slot in said tubular piston shaft, said second spring being compressed by the downstroke of the piston, and maintained compressed by the valve rod during the upstroke of the piston, said second spring being released from compression by said upward movement of the valve rod and thereby springing the valve to a full open position and maintaining it open until the next successive downstroke of the piston compresses said spring and thereby moves the valve rod and valve to closing relation with the said outlet opening.

2. A fluid operated motor as set forth in claim 1, and in which there is a control valve member in each of the inlet and outlet conduits of fluid through said inlet and outlet.

3. A fluid motor apparatus of the character described as set forth in claim 1, the outlet of the pressure chamber having capacity for flow greater than the inlet.

4. A fluid motor as set forth in claim 1, and in which the connection between said second spring means and the valve rod is a bar extending transversely through and loosely longitudinally slidably in the slot in the tubular piston shaft and having connection to the valve rod for unison movement with said valve rod, said spring being tensioned for expansion against said bar.

5. A fluid operated motor as set forth in claim 1, the cylinder chamber having a tubular axial extension, said piston shaft being reciprocable in said extension, said second spring member being coiled around said extension, the connecting means between said second spring and valve rod comprising a bar extending transversely through and loosely and longitudinally slidably in the slot in the tubular piston shaft and having connection to the valve rod for unison movement with the valve rod.

6. A fluid motor apparatus including a cylinder chamber, a piston reciprocable in the cylinder chamber providing a pressure chamber at one end of the cylinder having an inlet and an outlet for the operating fluid, a tubular piston shaft having one of its ends connected axially to the piston and extending therefrom beyond the cylinder chamber, said shaft having an axially elongated slot trans- 6 versely therethrough, a transverse cross-arm at the opposite end portion of the shaft for connection to apparatus to be operated by the motor, a first contact member 6 mounted at the cross-arm end of the piston shaft, a valve rod slidably mounted coaxially within the tube of the piston shaft and having one of its end portions extending beyond the cross-arm and said first contact member, the opposite end of said valve rod extending beyond the piston coaxial With the outlet opening of the pressure chamber, a second contact member mounted at said extended end portion of the valve rod, one of said contact members being adjustable longitudinally of said rod, said con-tact members being adapted for relative contact responsive to the upward expansive stroke of the piston, a disc valve at said opposite end of the valve rod adapted to open and close the outlet of the pressure chamber responsive to reciprocation of the valve rod, said valve being initially opened by the contact of said contact members, a spring means adapted for tension and compression responsive to reciprocation of the valve rod, means connecting said spring means with the valve rod whereby the valve rod is reciprocated in unison with the compression and expansive tension of said spring means, said last mentioned connecting means being s'lidable in the elongated transverse slot of the said piston shaft, said spring means being compressed by the downward stroke of the piston and maintained compressed by the valve rod during the upper stroke of the piston, and the expansive tension of said spring being adapted for springing the valve rod to a full open position when the said contact members initially raise the valve rod and valve to release a degree of pressure in the pressure chamber.

7. A fluid motor as set forth in claim 6, and in which there is a transverse bar extending tnansversely loosely and slidably through the slot in the tubular piston shaft and having connection to the valve rod for unison movement with said valve rod, said bar being actuated by the expansive tension of said spring means to move said valve rod to open the valve widely and quickly.

8. A fluid operated motor having the elements of claim 6 and in which one end of the cylinder chamber has a tubular guiding extension and the tubular piston shaft is reciprocated through said guide extension, and said spring means is mounted circumferen-ti'ally of said guide extension.

9. A fluid motor apparatus of the character described as set forth in claim 6, the said piston shaft, cross-arm and said first contact member being reciprocable in by the piston.

10. A fluid motor as set forth in claim 6 and in which the disc valve is flexible.

11. A fluid operated motor having the elements of claim 6, and in which there is a resilient bumper means in the valve-end of the compression chamber for receiving thereagainst the down stroke of the piston.

12. A fluid motor as set forth in claim 6 and which includes valve means for controlling the inlet and the outlet of said pressure chamber.

References Cited in the file of this patent UNITED STATES PATENTS 593,258 Watson Nov. 9, 1897 1,667,559 McCaleb Apr. 24, 1928 1,910,644 Smith May 23, 1933 2,704,998 Day et a1. Mar. 29, 1955 

